Substantially tubular-shaped cartons (also called sleeve-type cartons) are often used for packaging multiples of articles such as beverage cans or bottles. Such cartons are often packaged in a continuous-motion packaging machine wherein a continuous stream of articles such as beverage cans is loaded into one or more ends of a continuous stream of open-ended cartons. In such a packaging machine, flight bars typically transport the open-ended cartons. U.S. Pat. No. 3,990,572 to Fishback and U.S. Pat. No. 5,019,029 to Calvert are examples of the packaging methodology described.
The flight bars in a continuous-motion packaging machine are typically transported on an endless chain and spaced apart at intervals corresponding to the width of the opening of cartons that are to be loaded. The spacing between flight bars is often referred to as the “pitch” of the flight bars or the machine. FIG. 1 is a side elevational schematic illustration of the pitch of a flight bar arrangement. In the illustration, cartons 2 positioned between flight bars 6 and supported upon a surface 4 are transported by the light bars in direction “D” along the support surface. The pitch of the apparatus is: denoted by the letter “P” and is illustrated as the distance between flight bars, and, in turn, is based upon the width of the carton 2 opening shown.
As stated above, the pitch of a packaging machine is related to the width of the open end of a carton to be loaded. The width of a carton is, in turn, related to the width of articles, such as beverage cans or bottles, that the carton is designed to hold. The overall width of a carton is typically a multiple of the widths of individual articles to be packaged. For beverage cans or bottles, the width is the diameter of the substantially cylindrical portion of the article. In a packaging operation, it is often desirable to produce packages of different configurations or packages that contain different numbers of articles. In these instances, particularly when a smaller package is desired, it is often necessary to use a carton that has a narrower width at its open end.
A carton having a widthwise-narrower open end, because it is a narrower carton, requires a lesser pitch for flight bars. The problem is illustrated in FIG. 2, which is a schematic illustration showing a smaller carton in a machine set at a greater pitch. The end opening of the carton 10 has a width “w” that is less than the pitch P of the machine. The carton 10 does not receive adequate support because it is engaged (if at all) by only one of the flight bars. Thus, in general, the packaging machine must be modified to adequately handle the carton 10 of smaller opening width.
A problem in attempting to modify a packaging machine to accommodate a different carton than the machine is set for is that is that it is generally difficult to modify a packaging machine, if possible at all, to change its pitch. When a change-over (or conversion) to a different pitch is possible, the procedure is typically time-consuming, tedious and costly. The change-over operation is typically costly not only because of labor and parts but also due to lost production because packages are not produced during the conversion process. Even after the necessary parts have been changed, the machine may require extensive adjustments to operate properly at a different pitch
Thus, it can be appreciated that it would be useful to have a method for packaging a carton whose opening for loading is less than the pitch of the packaging machine.